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C++ API File Reference

#include "defun-dld.h"
#include "error.h"
#include "gripes.h"
#include "oct-obj.h"
#include "utils.h"
#include "oct-map.h"
#include "MatrixType.h"
#include "SparseCmplxLU.h"
#include "SparsedbleLU.h"
#include "ov-re-sparse.h"
#include "ov-cx-sparse.h"

Include dependency graph for


 DEFUN_DLD (luinc, args, nargout,"-*- texinfo -*-\n\ @deftypefn {Loadable Function} {[@var{l}, @var{u}, @var{p}, @var{q}] =} luinc (@var{a}, '0')\n\ @deftypefnx {Loadable Function} {[@var{l}, @var{u}, @var{p}, @var{q}] =} luinc (@var{a}, @var{droptol})\n\ @deftypefnx {Loadable Function} {[@var{l}, @var{u}, @var{p}, @var{q}] =} luinc (@var{a}, @var{opts})\n\ @cindex LU decomposition\n\ Produce the incomplete LU factorization of the sparse matrix @var{a}.\n\ Two types of incomplete factorization are possible, and the type\n\ is determined by the second argument to @dfn{luinc}.\n\ \n\ Called with a second argument of '0', the zero-level incomplete\n\ LU factorization is produced. This creates a factorization of @var{a}\n\ where the position of the non-zero arguments correspond to the same\n\ positions as in the matrix @var{a}.\n\ \n\ Alternatively, the fill-in of the incomplete LU factorization can\n\ be controlled through the variable @var{droptol} or the structure\n\ @var{opts}. The UMFPACK multifrontal factorization code by Tim A.\n\ Davis is used for the incomplete LU factorization, (availability\n\ @url{})\n\ \n\ @var{droptol} determines the values below which the values in the LU\n\ factorization are dropped and replaced by zero. It must be a positive\n\ scalar, and any values in the factorization whose absolute value are\n\ less than this value are dropped, expect if leaving them increase the\n\ sparsity of the matrix. Setting @var{droptol} to zero results in a\n\ complete LU factorization which is the default.\n\ \n\ @var{opts} is a structure containing one or more of the fields\n\ \n\ @table @code\n\ @item droptol\n\ The drop tolerance as above. If @var{opts} only contains @code{droptol}\n\ then this is equivalent to using the variable @var{droptol}.\n\ \n\ @item milu\n\ A logical variable flagging whether to use the modified incomplete LU\n\ factorization. In the case that @code{milu} is true, the dropped values\n\ are subtracted from the diagonal of the matrix U of the factorization.\n\ The default is @code{false}.\n\ \n\ @item udiag\n\ A logical variable that flags whether zero elements on the diagonal of U\n\ should be replaced with @var{droptol} to attempt to avoid singular\n\ factors. The default is @code{false}.\n\ \n\ @item thresh\n\ Defines the pivot threshold in the interval [0,1]. Values outside that\n\ range are ignored.\n\ @end table\n\ \n\ All other fields in @var{opts} are ignored. The outputs from @dfn{luinc}\n\ are the same as for @dfn{lu}.\n\ \n\ Given the string argument 'vector', @dfn{luinc} returns the values of @var{p}\n\ @var{q} as vector values.\n\ @seealso{sparse, lu}\n\ @end deftypefn")

Function Documentation

DEFUN_DLD ( luinc  ,
args  ,